# high frequency sawtooth oscillator

#### DominusDRR

Joined May 25, 2009
26
Is there a diagram of a high frequency sawtooth oscillator? 100MHz​

I'm going to use HFA1109 Amp Op.​

Fabián​

#### Wendy

Joined Mar 24, 2008
21,839
At that frequency it is going to be hard. You know how harmonics relate to waveforms, right?

#### KL7AJ

Joined Nov 4, 2008
2,208
Indeed....that's even pushing the recovery time of a xenon relaxation oscillator!

eric

#### beenthere

Joined Apr 20, 2004
15,808
Perhaps you could say why a sawtooth waveform is necessary?

#### DominusDRR

Joined May 25, 2009
26
At that frequency it is going to be hard. You know how harmonics relate to waveforms, right?
Yes. Definitely, I know about harmonics. I am not an expert in high frequency electronics, but I hope I will generate voltage signal​

#### DominusDRR

Joined May 25, 2009
26
Perhaps you could say why a sawtooth waveform is necessary?
I need to generate this signal to compare with other lower frequency signal. Something like a PWM or SPWM

Fabian​

#### bertus

Joined Apr 5, 2008
19,934
Hello,

Why do you need 100 Mhz?
What is the maximum frequency you use for the other comparing part?

Greetings,
Bertus

#### DominusDRR

Joined May 25, 2009
26
Hello,

Why do you need 100 Mhz?
What is the maximum frequency you use for the other comparing part?

Greetings,
Bertus

The other is 1MHz @ 10 MHz

#### Wendy

Joined Mar 24, 2008
21,839
Thing is, you're frequency response is going to be way past 500Mhz. That is the 5X harmonic. For a decent waveform you'll need really high frequency response.

At that frequency making a square wave is even harder, for the same exact reason. Square waves are usually used to generate triangle waves, but I think we can say this won't be practical at this frequency. The logic family ECL operates in this region, and gets around it by deliberately rounding the edges. A continuous logic chain in ECL resembles a sine wave more than a square wave.

#### DominusDRR

Joined May 25, 2009
26
And.. a DDS. Is it best?

#### millwood

Joined Dec 31, 1969
0
Hello,

Most Direct Digital Synthesysers will give a square wave or sinus as output.
Take a look at this DDS from this german hamradio site:
http://www.box73.de/catalog/product_info.php?cPath=112_113&products_id=1869
There you will also find a dataheet.

Greetings,
Bertus
that's an interesting design.

1) the mcu takes usb signal and sends out i2c. I would love to see their source code, for that.

2) the si570 is quite amazing. programmable oscillator. conceiveably, you can just take a mcu to control that with up/down buttons but controlling it with a pc through usb must be fun.

#### millwood

Joined Dec 31, 1969
0
the way they do tempco compensation is very smart.

it looks like a well thought-out and well designed package.